The fuselage, wings, and empennage of an aircraft typically include stringers that are coupled to skin structures that form the smooth aerodynamic outer surfaces of the fuselage, wings, and empennage. The stringers and skin structures cooperate to provide flexural and torsional stiffness to these sections of the aircraft. Traditionally, the fuselage, wings, and empennage surfaces and the associated stringers are fabricated from metal, such as aluminum, steel, or titanium. The stringer may include a web portion, such as a planar wall, that is generally oriented in a direction approximately perpendicular to the skin structure and extends in a generally lengthwise direction along the fuselage and empennage and in a generally span-wise direction along the wing so that the web portion provides resistance to bending. A flange portion may be positioned on one or both of the longitudinal edges of the web portion to provide increased rigidity and support to the stringer. The flange portion along one of the longitudinal edges of the web portion can also be used as an attachment surface for attaching the stringer to the skin structure.
Fiber reinforced composite materials are widely used in a variety of commercial and military aircraft products as a substitute for metals, particularly in applications where relatively low weight and high mechanical strength are desired. The material is generally comprised of a network of reinforcing fibers that are arranged in layers or plies. The layers include a resin matrix that substantially wets the reinforcing fibers and that is cured to form an intimate bond between the resin and the reinforcing fibers. The composite material may be formed into a structural component by a variety of known forming methods, such as extrusion, vacuum bagging, autoclaving, and/or the like.
The skins and stringers for various sections of aircrafts are transitioning from metallic materials to fiber reinforced composite materials. However, the manufacture of stringers and stringers affixed to skin structures can be quite time consuming. As there can be up to almost 6.5 kilometers of stringers in aircraft wing alone, the manufacture of stringers by hand is time and cost prohibitive. In addition, the hand manufacture of stringers may cause defects and non-conformities that compromise the rigidity and support of the stringer.
Accordingly, it is desirable to provide methods for fabricating reinforced composite structures for aircraft, such as I-stringers, that can be prepared by batch or continuous automated methods. In addition, it is desirable to provide devices for use in such methods. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.